Using tablet PC with Intel Atom Bay Trail-T Z3735D CPU, Gen7 iGPU. Default KDE 5.
Knob for changing brightness is available, I can move it, but it causes no change for bightness.
When system after idle period tries to turn off screen: screen become dark, but backlight is on. After moving cursor or tapping screen it turns on, but flickers. This flickering remains after reboot, it is difficult to eradicate this error. But it turns out that changing colour temperature with KDE’s Night Color mode makes screen to behave normally.
KDE’s Night Color mode works OK - it changes screen colour temperature.
I used modesetting and Intel (from xf86-video-intel package) drivers - no changes.
I examined dmesg, found errors and warnings, some of them about staging drivers.
I loaded new TW Live ISO, some things improved. But this TW Live ISO is unusable on my hardware - only 2 GB of RAM (1.6 GB available) and USB 2.0 port.
I will try newer kernel.
I’ve added Kernel:stable:Backport repo and performed full repo vendor change for it.
After reboot: I can adjust brightness. Screen can be turned off, but it flickers after that procedure.
Dmesg brings some warnings. Will investigate further.